The present invention relates generally to pads for corns, calluses and warts, and more particularly, to an improved corn, callus and wart removing pad.
Corns are a painful type of hyperkeratosis, found principally over prominent toe joints and between toes. There are two common types of corns: Heloma Durum and Heloma Molle. Heloma Durum (hard corn) is a hyperkeratotic lesion which appears over a bony prominence and may have a deep nucleus. These corns are normally very tender and painful. The Heloma Molle (soft corn) is a hyperkeratotic lesion which is found between the toes. The soft corn results from pressure exerted between adjacent toes and is soft due to moisture between the toes.
A callus may be a diffuse or circumscribed area of hyperkeratosis at a site of repeated pressure and friction. In cases where there is a forefoot imbalance the plantar callus may be found where the metatarsal heads are most prominent.
Plantar warts are simple papillomas caused by a virus. Plantar warts differ from calluses and are not necessarily found over bony prominences. They may be sharply circumscribed with their edges clearly demarcated from the surrounding skin. Their center is darker than the surrounding skin and their may have a mosine appearance. Warts are usually painful to squeezing and often exhibit pain from the pressure of walking.
Medicated pads are known for placement over corns, calluses and warts, and which contain an ingredient, such as 40% salicylic acid by weight in a rubber based vehicle, for removing corns, calluses and warts. For example, such pads are sold by Schering-Plough Healthcare Products, Inc. of Memphis, Tenn. under the house trademark xe2x80x9cDR. SCHOLL""Sxe2x80x9d, and under the particular trademarks xe2x80x9cCLEAR AWAYxe2x80x9d and xe2x80x9cONE STEPxe2x80x9d.
Specifically, with such known pads, there is a relatively thick center cushion formed of ethylene foam or ethylene vinyl acetate (EVA), polyethylene or like material having a circular opening, and an elongated vinyl film secured to the upper surface of the center cushion section and extending outwardly from opposite sides thereof. An adhesive is applied to the lower surfaces of the entire thick center cushion section and the elongated portions of the vinyl film that extend outwardly from opposite sides of the thick center cushion section. In effect, the shape is similar to a conventional adhesive bandage, but with adhesive material also provided on the lower surface of the center cushion.
A disk containing the salicylic acid is provided in the recess, and is separated from the remainder of the center cushion and from the vinyl strip by a barrier layer. A release liner is provided on the underside of the pad, and extends along the entire center cushion and vinyl film. Also, a paper release tab is releasably secured to the lower surface of one free end of the vinyl strip.
In use, a person removes the release liner, thereby exposing the adhesive layer applied to the lower surfaces of the entire thick center cushion and the elongated portions of the vinyl film that extend outwardly from opposite sides of the thick center cushion. The lower surfaces of the entire thick center cushion and the elongated portions of the vinyl film that extend outwardly from opposite sides of the thick center cushion are then secured to the person""s skin, such that the medicated disk covers the corn, wart or callus to be removed. The paper release tab is then removed.
However, such product has a generally high profile, that is, a relatively large cross-sectional thickness. Also, this arrangement requires adhesive to be applied to both the lower surfaces of the entire thick center cushion and the elongated portions of the vinyl film that extend outwardly from opposite sides of the thick center cushion.
More importantly, the center cushion is water impermeable. When the person perspires, moisture and liquid can form an interface layer between the medicated disk and the skin containing the corn, callus or wart. Also, such interface layer tends to weaken the adhesive, so that the pad tends to fall from the skin after a relatively short period of time in the presence of such liquid interface layer.
A further problem with such product is that the salicylic acid tends to evaporate and be lost to the environment over time. For example, in tests performed in accelerated aging conditions under a temperature of 40xc2x0 C. and 75% relative humidity, over a three month period, for a product starting with 42% salicylic acid by weight, only 36-37% salicylic acid by weight remained. This represents a very large loss of medicament.
It is known to provide bandages out of other materials. For example, it is known to provide trauma bandages made from a hydrocolloid adhesive layer. However, these trauma bandages do not include any transdermal device containing any keratolytic agent (skin removing) or other medicaments.
Accordingly, it is an object of the present invention to provide a medicated pad that overcomes the problems with the aforementioned prior art.
It is another object of the present invention to provide a medicated pad particularly adapted for removing warts, calluses and corns.
It is still another object of the present invention to provide a medicated pad which uses less adhesive than conventional medicated pads.
It is yet another object of the present invention to provide a medicated pad in which the center hydrocolloid adhesive layer performs the dual function of an adhesive layer and a cushion.
It is a further object of the present invention to provide a medicated pad in which adhesion is increased in the presence of a liquid.
It is a still further object of the present invention to provide a medicated pad which will adhere to a person""s skin for a longer period of time.
It is a yet further object of the present invention to provide a medicated pad in which less medicament will be lost to the environment.
It is another object of the present invention to provide a medicated pad having a longer shelf life than conventional medicated pads.
In accordance with an aspect of the present invention, a medicated pad includes a center cushion layer having adhesive and liquid absorbing properties, said center cushion layer having a periphery and an underside, a medicated plaster secured to the underside of the center cushion layer, a barrier layer interposed between the medicated plaster and the center cushion layer to prevent diffusion of any medicament in the medicated plaster to the center cushion layer, an outer layer secured to the center cushion layer, the outer layer at least having a border extending outwardly of the layer of center cushion layer, the border having an underside, and a layer of adhesive material on the underside of the border. Preferably, the medicament includes salicylic acid, and the medicated plaster is secured at a substantially central position of the center cushion layer.
The barrier layer is made from a material selected from the group consisting of polyester film, polypropylene and polyolefin films.
A release liner is releasably secured to the underside of the center cushion layer. The release liner is made from a material selected from the group consisting of polyester film, polypropylene film, polyethylene film, polyolefin films, paper and polyethylene/paper laminates or film/paper laminates.
A release tab is releasably secured to an upper surface at one side of at least one of the center cushion layer and the outer layer. The release tab is made from a paper material or polymer film.
The center cushion layer may also include a recess at the underside thereof, and the barrier layer and the medicated plaster are positioned at least partially in the recess. In one embodiment, the recess includes a side wall and a bottom wall, the barrier layer is interposed between the bottom wall and the medicated plaster, and the medicated plaster is spaced apart from the side wall of the recess. In another embodiment, the recess includes a side wall and a bottom wall, and the barrier layer is interposed between the side and bottom walls of the recess and the medicated plaster.
In accordance with another aspect of the present invention, a medicated pad includes a layer of hydrocolloid adhesive material having a periphery and an underside, a medicated plaster secured to the underside of the layer of hydrocolloid adhesive material, a barrier layer interposed between the medicated plaster and the layer of hydrocolloid adhesive material to prevent diffusion of any medicament in the medicated plaster to the layer of hydrocolloid adhesive material, an outer layer secured to the layer of hydrocolloid adhesive material, the outer layer at least having a border extending outwardly of the center cushion layer, the border having an underside, and a layer of adhesive material on the underside of the border.
In accordance with still another aspect of the present invention, a medicated pad includes a layer of hydrogel adhesive material having a periphery and an underside, a medicated plaster secured to the underside of the layer of hydrogel adhesive material, a barrier layer interposed between the medicated plaster and the layer of hydrogel adhesive material to prevent diffusion of any medicament in the medicated plaster to the layer of hydrogel adhesive material, an outer layer secured to the layer of hydrogel adhesive material, the outer layer at least having a border extending outwardly of the center cushion layer, the border having an underside, and a layer of adhesive material on the underside of the border.
The above and other features of the invention will become readily apparent from the following detailed description thereof which is to be read in connection with the accompanying drawings.